Material In Production Of Concrete Research Articles

Selection of Either (Fly Ash, Rubber And Rice Husk) Material for Rigid Pavement: Review

Abstract: Road transportation plays a crucial role in India's economic development, providing cost-effective, accessible, and adaptable means of transportation for both passengers and freight. Pavement, as a key component of highway design, must withstand vehicular loads and foot traffic while ensuring safe and efficient movement. This paper reviews existing literature on pavement materials, focusing on sustainable alternatives such as fly ash-based geopolymers, basalt fiber-reinforced concrete, and asphalt mixtures incorporating recycled aggregates and rubber. Additionally, it proposes the combination of rice husk and crumb rubber in concrete as a sustainable approach for pavement construction. The study aims to evaluate the mechanical properties of concrete with partial material replacements through experimental investigation. By addressing gaps in durability studies, comparative analysis, and non-destructive testing, this research seeks to provide valuable insights into the feasibility and sustainability of utilizing waste materials in concrete production. Ultimately, it aims to contribute to advancing sustainable practices in the construction industry and addressing the challenge of waste accumulation.

Strength Characteristics and Rheological Behavior of a High Level of Fly Ash in the Production of Concrete.

This study investigates the valorization of coal fly ash (FA-C) generated by the Jerada thermal power plant, aiming to address the pressing need for sustainable construction practices and reduced greenhouse gas emissions in the concrete industry. It is widely used as a pozzolanic material. The key objective is to harness the potential of FA-C as a supplementary material in concrete production, which not only reduces costs but also contributes to environmental sustainability. To achieve this objective, various concrete mixtures were formulated, with FA-C serving as a partial substitute for cement at percentages ranging from 15 to 50%. According to ASTM standards, compressive strength tests were conducted on standard-sized cylinders at 7 and 28 days. The results revealed that the blend containing 15% FA-C exhibited the highest compressive strength, indicating its effectiveness as a concrete additive. Furthermore, this study delves into the rheological properties of concrete mixes, an essential aspect of successful concrete processing. It was observed that a higher replacement level of FA-C significantly improved the rheology, leading to reduced water demand and a linear decrease in plastic viscosity over time. The rheological parameters stabilized after a certain period, demonstrating the controllability of concrete flow behavior with FA-C. The investigation also employed three analytical methods-Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM)-to comprehensively analyze both raw materials and processed samples. FTIR analysis highlighted the minimal impact of FA particles on hydration product formation, emphasizing the role of FA-C in enhancing the concrete's strength. XRD analysis confirmed the presence of an amorphous phase crucial for FA's reactivity. SEM observations revealed that concrete with 15% FA-C exhibited a more uniform microstructure with aluminosilicate gel, while 50% FA-C mixes showed increased porosity and nonhomogeneity due to unreacted FA particles.

Utilization of Aluminum Dross as a Cement Replacement Material for Sustainable Concrete Development

The recovery of aluminum from aluminum dross waste involves intensive cost and energy. Therefore, there is a need for its utilization as an engineering material by using it as a filler material in concrete production. The cement industry is battling numerous difficulties due to the shortage of raw materials and sustainability issues related to the emission of CO2 into the atmosphere. On this basis, the present study aims to utilize aluminum dross as a replacement material for cement to develop sustainable concrete. In this study, the results of control concrete samples were compared to the results of concrete samples containing aluminum dross by 5%, 10%, and 15% by weight of cement. The mechanical and chemical analysis of the M40 grade concrete employing aluminum dross as a replacement material in cement was analyzed. It was noticed that the best percentage of aluminum dross was 10%, providing better results compared with conventional concrete. It recorded the highest strength of 41.3MPa. Thermogravimetric analysis was conducted in which weight loss, decomposition of hydration compounds, and percentage of calcium hydroxide from concrete were determined. Scanning electron microscopy analysis showed that the density of concrete increased owing to the presence of ettringite needles and calcium silicate hydrate in the matrix. Moreover, the toxicity analysis revealed that the ammonia content and the leachability of trace elements from the concrete were both low and within acceptable ranges. The findings indicate that aluminum dross has positive results as an additional cementitious material in concrete to overcome environmental problems related to dross management and reduce cement utilization, producing more sustainable concrete.

Effect of partial sand replacement with PVC and glass mix on flexural behavior of concrete

Waste in millions of tons is produced in the world each year and most of it is not recyclable. Furthermore, recycling waste consumes energy and produces pollution. In addition, the accumulation of waste in suburbs and disposal of waste is dangerous for the environment. Using waste material in concrete production is an appropriate method for achieving two goals i.e. eliminating waste and adding positive properties in concrete. Since the green concrete industry is expanding, it is necessary to evaluate concrete that contains waste from all aspects to determine its capability. This research consists of analyzing the use of waste as a partial substitute for sand. Leading waste material that has been used as substitutes is highlighted and the characteristic of the resulting concrete is evaluated in this research. Among other findings, rubber was found to have improved fire resistance and ductility in concrete, and agricultural and Polyethylene terephthalate (PET) wastes were successfully used in non-structural concrete, while glass helped to improve thermal stability. In this research aggregate and sand is replaced by waste materials of Polyvinyl Chloride (PVC) and Glass to check their effect on the mechanical properties. Lab tests were performed to analyze the flexural behavior of concrete samples having waste material. The results show how partial replacement of sand affects the behavior of concrete and based on that specify the conditions where it can be used. The results show that Young’s modulus, maximum bending stress, and bending deflection varies with the percentage composition of PVC and glass. Bedding stress and bending deflection decrease with PVC and glass composition up to 35%. Although Young’s modulus is fluctuating bending deflection will decrease.

Mechanical, freeze-thaw, and sorptivity properties of mortars prepared with different cement types and waste marble powder

The cement production process contributes significantly to CO2 gas emissions and environ- mental pollution. To reduce this adverse effect, the substitution of waste marble powder as a cement additive was investigated. In this study, the properties of mortar specimens were analyzed by using waste marble powder as a partial substitute for three different cement types: CEM I 42.5R Ordinary Portland Cement (OPC), CEM II/B-L 42.5R White Cement (WC) and CA-40 Calcium Aluminate Cement (CAC). Waste marble powder has been replaced with ce- ment at 5%, 10%, and 15%. The compressive and flexural strength, capillary water absorption, and sorptivity values of the prepared mixtures were determined before and after freezing and thawing. It was carried out after 28 days of water curing on 50 x 50 x 50 mm specimens for compressive strength and 160 x 40 x 40 mm specimens for flexural strength test. Freeze-thaw testing of the mixture samples was conducted according to ASTM C666 Procedure A. Test re- sults showed that the highest compressive strength before freeze-thaw was obtained in calcium aluminate cement-based mortars containing 10% by weight waste marble powder replacement for cement. The appropriate waste marble powder ratio was determined as 10% in all cement types used in the study. Before freeze-thaw, the mechanical properties of CAC-based mixtures were higher than those of other cement types. However, as the number of freeze-thaw cycles increased, the strength losses were more significant compared to OPC and WC.

The Environmental Impact of Reusing Post-Earthquake Demolition Waste: İskenderun Case Study

Producing recycled aggregate from construction and demolition waste generated by earthquakes
 and using it as raw material in concrete production would be effective for urgent waste
 management after disasters and to reduce the environmental impact of concrete production by
 decreasing resource use. In this study, the life cycle assessment (LCA) method was used to
 examine the environmental implications of concrete produced using recycled aggregates (RA)
 derived from construction and demolition waste (CDW) of buildings demolished after the
 earthquake that struck Iskenderun and was centered in Kahramanmaraş. In addition, the
 environmental consequences of an equal volume of concrete produced in the same location
 utilizing natural aggregates (NA) were assessed. For the LCA of these two types of concrete,
 openLCA software and the ReCiPe midpoint database were used. LCA was conducted
 considering terrestrial ecotoxicity, climate change, terrestrial acidification, photochemical
 oxidant formation, marine ecotoxicity, human toxicity, freshwater ecotoxicity, ozone depletion,
 particulate matter formation, marine eutrophication, and ionizing radiation impact factors. The
 results show that cement has the highest impact on the environment by far. RAC (recycled
 aggregate concrete) has a lower environmental impact than NAC (natural aggregate concrete), in
 general.

Review: Development Trends in the Reuse of Waste Materials in Concrete Production

This comprehensive review explores the development trends in the reuse of waste materials in concrete production, highlighting their critical role in advancing sustainable construction practices. We conduct an in-depth comparative analysis of various waste materials such as fly ash, slag, and recycled aggregates, and their impact on the properties and performance of concrete. The chapter also presents innovative case studies, such as the use of recycled glass and plastic waste in concrete, demonstrating real-world applications of these sustainable practices. Additionally, the review discusses technological advancements that facilitate the efficient processing and integration of waste materials into concrete. The overall focus is on balancing environmental benefits with the technical, economic, and social challenges inherent in adopting these sustainable methods. This review underscores the urgency and potential of integrating waste materials into concrete production, providing insights into the future directions of sustainable construction.

Utilization Of Kota Stone Slurry Powder and Recycled Aggregate for Rigid Pavement

Utilization Of Kota Stone Slurry Powder and Recycled Aggregate for Rigid Pavement

Characterization of net-zero pozzolanic potential of thermally-derived metakaolin samples for sustainable carbon neutrality construction

Metakaolin (MK) is one of the most sustainable cementitious construction materials, which is derived through a direct heating procedure known as calcination. Calcination process takes place substantially lower temperatures than that required for Portland cement, making it a more environmentally sustainable alternative to traditional cement. This procedure causes the removal of hydroxyl water from the naturally occurring kaolin clay (Al2Si2O5(OH)4 with MK (Al2O3·2SiO2) as its product. Kaolin naturally exists in large amount within 5°29′N–5°35′N and 7°21′E–7°3′E geographical coordinates surrounding Umuoke, Obowo, Nigeria. Alumina and silica are the predominant compounds in MK, which provide it with the pozzolanic ability, known as the 3-chemical pozzolanic potential (3CPP), with high potential as a cementitious material in concrete production and soil stabilization. Over the years, researchers have suggested the best temperature at which MK is derived to have the highest pozzolanic ability. Prominent among these temperature suggestions were 800 °C (3CPP of 94.45%) and 750 °C (3CPP of 94.76%) for 2 h and 5 h’ calcination periods, respectively. In this research paper, 11 different specimens of Kaolin clay obtained from Umuoke, Nigeria, were subjected to a calcination process at oven temperatures from 350 to 850 °C in an increment of 50 °C for 1 h each to derive 11 samples of MK. The MK samples and Kaolin were further subjected to X-ray fluorescence), scanning electron microscopy (SEM) and X-ray diffraction (XRD) Brunauer–Emmett–Teller (BET) tests to determine the microstructural behaviour and the pozzolanic properties via the 3CPP as to exploit the best MK with the highest cementing potential as a construction material. The results show that the MK heated at 550 °C and 800 °C produced the highest pozzolanic potentials of 96.26% and 96.28%, respectively. The enhancement in pozzolanic potential at optimum calcination temperature is attributed to an increase in the specific surface area upon calcination of kaolinite confirmed by BET results. The SEM and XRD results further supported the above result with the strengthened crystal structure of the MK at these preferred temperatures. Generally, 550 °C is more preferred due to the less heat energy needed for its formulation during 1 h of calcination, which outperforms the previous results, that suggested 750 °C and 800 °C in addition to longer hours of heat exposure.

PERFORMANCE EVALUATION OF PALM OIL CLINKER AS CEMENT AND SAND REPLACEMENT MATERIALS IN FOAMED CONCRETE

Cellular lightweight concrete (CLC), also known as foamed concrete, has been extensively used in construction for decades. Foamed concrete’s properties include low density, excellent thermal conductivity, great workability, and selfcompaction; these features enable foamed concrete to be utilized in various contexts. However, the excessive use of conventional materials in concrete production harms the environment. Therefore, using agro-waste as a material to construct ecologically sustainable structures has numerous practical and financial benefits. Palm oil clinker (POC) is a waste product resulting from solid waste combustion during palm oil extraction. This research focused on the properties of foamed concrete with POC at 0%, 25%, 50%, 75%, and 100% as the fine aggregate replacement to develop lightweight foamed concrete (LFC) with a density of 1300 kg/m3. Besides, the potential of POC powder (POCP) and thermally activated POCP (TPOCP) at 0%, 10%, 20%, and 30% as cement replacements was examined. The development of compressive strength during a 90-day curing period was investigated. In addition, tensile and flexural strengths were assessed and reported, and the elastic modulus of the LFC was discussed. The transport properties of water absorption, porosity, and sorptivity were also investigated. The durability of concrete derivatives can exhibit the product’s resistance to chemical attacks and environmental conditions. After 75 days of immersion in hydrochloric acid and magnesium sulfate, the chemical resistivity of the produced LFC was determined by measuring the loss in weight and compressive strength. In addition, the effects of elevated temperatures on the LFC were determined by analyzing the mass loss and compressive strength degradation of specimens exposed to temperatures ranging from 200 to 800 °C. The test results demonstrated that the complete replacement of sand with POC enhanced the compressive strength of LFC by more than 50%. Similarly, POC-based LFC had higher flexural and tensile strengths than normal LFC. Besides, substituting 20% of cement with TPOCP could improve the strength of LFC by 23% during the initial curing days. Utilizing the optimal proportions of POC and POCP could enhance the residual strengths of LFC. Therefore, POC has the potential to be utilized as a fine aggregate and cementitious material to produce sustainable concrete.

Durability-related performance of recycled aggregate concrete containing alkali-activated municipal solid waste incinerator bottom ash

The increasing demand for sustainable construction materials has led to a growing interest in the use of recycled materials in concrete production. The main motivation for this research is to explore sustainable alternatives to conventional concrete mixes that can reduce the environmental impact of construction activities and address the growing issue of waste accumulation. For this reason, this study intends to evaluate the performance of alkali-activated concrete with different contents of fly ash (FA) and municipal solid waste incinerator bottom ash (MIBA). For this purpose, five compositions were considered, where the binder ratios were 100% cement, 100% FA, 75% FA/25% MIBA, 50% FA/50% MIBA and 25% FA/75% MIBA, all of which were produced with natural aggregates. Five additional mixes were produced by fully replacing the natural aggregate with recycled aggregate from mixed construction and demolition waste. A mix with 100% FA, fine natural aggregates and coarse recycled aggregates was also produced to understand the difference between the full use of recycled aggregates and their partial use. The conducted tests include compressive strength, water absorption by capillarity and immersion, chloride penetration, carbonation, and shrinkage (autogenous and total). The results showed that the substitution of FA with MIBA led to progressively worse durability-related performance, though manageable in given proportions. The incorporation of recycled aggregates led to an unexpectedly steep decline of ∼80% in compressive strength and overall durability performance in comparison with equivalent cement-based recycled aggregate concrete mixes. Nevertheless, the trend reverted in terms of shrinkage, wherein recycled aggregate-containing mixes presented the least dimensional variations. In the mechanical strength test, the curing of the alkali-activated concrete mixes in a CO2 chamber led to a considerable improvement (i.e. 5–15 MPa) in all tested mixes.

Waste ceramic as partial replacement for sand in integral waterproof concrete: The durability against sulfate attack of certain properties

Abstract Nowadays, the use of waste materials in concrete production is crucial for a clean environment and less concrete cost. This study aimed to enhance some mechanical properties of concrete utilizing integral waterproof (IWP) admixture and using waste ceramics as fine aggregate with finer particles to improve compressive strength and modulus of elasticity and absorption studied. Studies indicate increase in compressive strength and modulus of elasticity by using IWP only and also a reduction in absorption and by using ceramic powder as a replacement with normal sand, more advantages were achieved, i.e., the compressive strength increased from 41.7 to 47.8 MPa by replacing sand with some ceramic waste, and the modulus of elasticity increased from 25.22 to 29.61 GPa. The absorption lowered to only 1% while it was 1.96% for concrete without ceramic waste. Durability against sulfate attack was also studied in this research.

Potential Use of Scoria as a Cementitious Material for Green Concrete Production

The demand for cement, which is one of the key components of concrete, is high in Ethiopia, but it is the most expensive and environmentally unfriendly construction material. Due to the increasing concerns about the environment worldwide, researchers have started looking for other resources that can be used to reduce the pollution caused by the cement industry. One of the most effective ways to reduce the pollution caused by the cement industry is by using volcanic scoria powder as a partial replacement for cement in concrete production. Scoria is a locally available natural volcanic material in Ethiopia, especially around the rift valley regions. This natural resource can also be used to reduce energy consumption and the cost of production of cement. To investigate this study, nonprobability sampling techniques were adopted to collect samples from the study area. A differing proportion of scoria powder was considered as a partial replacement of cement after analyzing its characteristics, and its effect on the fresh and mechanical properties of hardened concrete was examined. The test results on the characteristics of scoria revealed that the material is suitable to be used as a supplementary cementitious material in concrete production; hence, its main constituents SiO2 + Al2O3 + Fe2O3 are higher than 70% as per ASTM C618. As the content of scoria powder replacement in cement is increased, it reduces the slump of freshly mixed concrete properties. The hardened concrete specimens made with 10%, 20%, and 30% partial replacement of cement with scoria achieved the specified minimum strength after 28 days of curing time. But concrete specimens made with 40% scoria content do not satisfy the minimum specified concrete strength even after 90 days. The significant strength achievement in scoria blended concrete specimens occurred when moving from 56 to 90 days of curing with 10% replacements. However, in reference specimens, this was observed during 28 days of curing times. The findings of this investigation revealed that scoria powder could replace cement by 30% for the production of normal concrete and it also has the potential to protect the environment from carbon dioxide emissions. These findings satisfy the basic strategy of green concrete production in worldwide.

Carbon sequestration from waste and carbon dioxide mineralisation in concrete – A stronger, sustainable and eco-friendly solution to support circular economy

The production of concrete is heavily reliant on the continuous mining of natural resources, with the majority component being the natural aggregates which make up about 70–75% of the concrete volume. As the emphasis shifts towards promoting sustainability through recycling all types of waste to create a closed-loop circular economy, it's vital to explore alternative waste materials that can replace traditional raw materials in concrete production. Biochar derived from different organic waste materials has shown to improve the strength properties of concrete. However, the majority of the research has focussed on using biochar as a cement replacement material with very low cement replacement levels. Therefore, this research focuses on significantly increasing the uptake of the pyrolysed form of organic waste (wood biochar) by using it as a replacement of fine aggregates at replacement levels of 10, 20 and 30 vol%. The biochar blended concrete showed an improvement of 63.9, and 45.6% and a reduction of 9.6% in the 7-day compressive strength results at 10, 20 and 30% replacement levels, respectively. At 28 days, the biochar blended concrete samples showed an improvement of 20.1, 22.6, and 16% in the compressive strength results at 10, 20 and 30% replacement levels, respectively. Separately, the 10% WBC blended concrete was also cured in a CO2 environment for 7 and 28 days. The results showed an improvement of 24.7 and 37.3 in the 28-day compressive strength results with the respective CO2 curing of 7 and 28 days, compared to the control mix.

Understanding the environmental, economic, and social impact of fly ash utilization on early-age high-strength mass concrete using life cycle analysis

High-strength mass concrete mixtures are a crucial component of numerous structures nowadays. However, concrete greatly impacts the environment, economy, and society. The impact of employing fly ash in early-age, high-strength mass concrete mixtures has not yet been quantified and documented in the literature. This study aims to evaluate the impact of early-age, high-strength mass concrete mixtures and provide insight into how the current practice might be enhanced to promote sustainability. The research examines concrete mix utilized in two bridges in the Philippines with the following design compressive strengths: 55 MPa at 7 days (7OPC), 55 MPa at 28 days (28OPC), and 55 MPa at 7 days with 20% fly ash as cement substitute (7FA20). Using SimaPro 9.3, a cradle-to-gate life cycle analysis was conducted to quantify their effects based on 18 midpoint and 3 endpoint categories. Results show higher impact of 7OPC on 17 midpoint and 3 endpoint indicators was observed than on 28OPC. The most significant midpoint impacts based on normalization are fossil resource scarcity, global warming potential, ozone formation, human carcinogenicity toxicity, and terrestrial ecotoxicity. The global warming potential of 7OPC was quantified to be 636 kg CO2 eq compared to 549 kg CO2 eq of 28OPC concrete. Utilizing fly ash decreased the damage to resources (11%), human health (16%), and the environment (16%). Analysis of concrete constituents indicated that using chemical admixtures to obtain early high strength contributed significantly to fossil resource scarcity and resource damage . The framework presented in this study may be used for assessing the sustainability of utilizing other waste materials in concrete production.

Rice-Husk and Sugarcane-Bagasse Ash as a Partial Replacement of Cement in Self-Compacting Concrete

The necessity for reasonable and sustainable different construction materials to cement in emerging countries cannot be underrated. However, cement among the constituent material in concrete production is broadly identified to be the most costly. Therefore, in developing countries, research into the use of alternative materials for civil and building construction is necessary due to the increasing cost of construction materials like cement. Alternative construction materials like agro and industrial wastes etc., are nowadays employed to substitute cement in concrete production. In this paper, Rice-Husk Ash (RHA) and Sugarcane-Bagasse Ash (SBA) as agro-wastes were used to replace cement partially in Self-Compacting Concrete (SCC) in order to determine their influence on the mechanical properties of the SCC hardened specimens. The percentage replacements used were 0%, 5%, 10%, 15% and 20% of the ashes in the corresponding concrete mixes. Concrete cubes and prism specimens were cast, cured and their mechanical properties (compressive and flexural strengths) were evaluated at 7, 14, 21 and 28 days. The results show that remarkable strength values of compressive and flexural strengths were manifested, when compared with the control specimens. In conclusion, it was established that 5% cement replacement of the ashes used was found to be a favorable value among the percentage replacements considered. Moreover, the study demonstrated the use of agro-wastes which may enhance the reduction of cement usage and will pave the way of innovative and sustainable construction.

Investigation into the Effect of Rice Husk Ash in Partial Replacement of Cement in Concrete

The purpose of this study was to investigate the properties of Rice Husk Ash (RHA) as a partial cement replacement material in concrete production based on analysis of its contribution to strength in comparison with Ordinary Portland Cement (OPC). The analysis was focused on: the chemical properties of RHA, workability, density, compressive strength, and tensile strength of concrete. The RHA was obtained from Mwea, Kirinyaga County, Kenya and burned in a kiln to produce white ash which was tested. Chemical analysis to determine the pozzolanic properties of RHA was done using the Gravimetric method, Flame Photometry and Atomic Absorption Spectroscopy while particle size distribution of RHA was carried out using sieve analysis and hydrometer analysis. Concrete mixes with different ratios of OPC to RHA binder were cast into cuboid and cylindrical samples. The binder was made by replacing OPC with RHA at intervals of 10% by mass to a maximum of 50% replacement. A binder, sand, and ballast ratio of 1:1.5:3 were maintained with a constant water-cement ratio of 0.6. The cast samples were subjected to water curing on the third day at room temperature. Workability tests were performed on fresh concrete while compressive strength tests and tensile strength tests were performed on hardened concrete in all the mixes. The results were compared with OPC concrete. Results indicated that Kenyan RHA has high silica, alumina, and iron oxide content of about 92%. The workability slightly improves with 10% partial replacement of OPC with RHA but decreases with further addition of RHA. It was also deduced that the optimal binder mix was 10% partial replacement of OPC with RHA however the compressive strength was lower than the OPC concrete by 2.3%. The tensile strength of concrete increased with the addition of RHA up to an optimum of 10%.

Numerical Optimization for the Design of Geopolymer Concrete Walls with Phase Change Materials in the Mediterranean Climate

The adoption of phase change materials (PCMs) is a promising solution for the improvement of building energy performances and indoor comfort, and the integration of geopolymer concrete (GPC) allows recycling materials and reducing the demand for raw materials in concrete production. Both materials contribute to reducing the carbon dioxide emission in the building lifecycle. In this frame, this paper proposes a complete numerical approach for selecting the optimal wall package made of GPC and PCMs in a Mediterranean climate. The first step of the method consists of a parametric analysis for evaluating the incidence on energy performance and thermal comfort of the main designing variables: insulation thickness, air cavity type and its thickness, and PCMs type. Then, assuming the discomfort hours as a limiting constraint, a multi-objective optimization is applied to a subset of solutions for determining the Pareto front solutions. The advantage of the proposed methodology is the combined evaluations of multiple variables with a simplicity in execution; for this reason, it is useful for other researchers aimed at studying innovative solutions. According to obtained results, the better exposure for the proposed wall package is the north or northeast one. The minimization of the cooling energy demand requires the adoption of two PCMs, on internal and external sides, with melting temperature of 26 °C. The optimization of yearly performance requires the adoption of the maximum insulation level on both sides and a not-ventilated air gap between the modules. The cooling and heating energy need can be reduced, respectively, by around −29% and −57%, compared to a reference configuration with vacuum insulation panels and thermal transmittance of 0.4 W/m2 K.

Use of lightweight materials for the production of low-density concrete: a literary review

Throughout the 20th century, the construction industry has been using large quantities of concrete. Consequently, the demand for natural aggregates has increased, making it necessary to counteract their use. In this context, this work aims at presenting a literature review of the use of lightweight materials to produce low-density concrete, whose thermal insulation is mainly made using lightweight aggregates. In this framework, 52 articles indexed between 2017 and 2021 in the Scopus database were reviewed. The results revealed that, by employing ceramsite sludge as an aggregate, a density of 1,251 kg/m3 can be obtained and, with expanded clay aggregates, compressive strengths from 17.7 to 66.1 MPa can be obtained. In conclusion, it was determined that the use of lightweight materials in concrete production can reduce its density, in addition to contributing to the reduction of environmental damage.

Performance Evaluation of Mechanical and Durability Properties of Fly Ash and Silica Fume Based Concrete for Sustainable Building Material

he intensive use of cement in construction is a significant environmental concern. To reduce the use of cement for energy consumption, the use of supplementary cementitious materials (SCMs) like Fly ash (FA) and Silica fume (SF) in concrete is an interesting solution. FA and SF-based construction materials offer a lot of potential as alternatives to ordinary portland cement (OPC) because of their high performance and environmental friendliness. The level of replacement and the necessity for additional cementitious content are critical considerations when choosing the most sustainable material for concrete production. To achieve long-term sustainability, the use of FA and SF in the construction industry is essential. Therefore, the authors attempted to identify the preferred material between FA and SF for sustainability by conducting a performance evaluation on the mechanical and durability properties of two binary mixes, i.e., FA and SF-based concrete mixes. The first binary blended concrete mix is prepared by replacing cement with FA at 20%, 30%, and 40% by weight, and the second mix is prepared with SF at 5%, 7.5%, and 10% by weight. The compressive strength (CS), flexural strength (FS), water sorptivity (WS), and rate of chloride penetration (RCP) of these two binary blended concrete mixes were studied. The results show that the incorporation of SF and FA has a significant impact on workability. The use of SF considerably increased the early and long-term strength of concrete, whereas FA lowered early age strength; nevertheless, it enhanced long-term strength. It was concluded that the SF contributed to better durability properties than FA. FA at 30\% and SF at 10\% exhibited the desired strength and durability than OPC, which can be used as a sustainable building material.